The probability that Janice will attend math class today is 62%. The probability that Ellie will attend math class if Janice attends is 100%. Ellie will not attend the class unless she hears from Janice first. What is the probability that both will attend the class?
a.) 73%
b.) 100%
c.) 81%
d.) 62%

Question

The probability that Janice will attend math class today is 62%. The probability that Ellie will attend math class if Janice attends is 100%. Ellie will not attend the class unless she hears from Janice first. What is the probability that both will attend the class?
a.) 73% 
b.) 100%
c.) 81%
d.) 62%

anonymous · Answer

@robtobey

anonymous · Answer

$$
\Pr(E|J) = \frac{\Pr(E\cap J)}{\Pr(J)}
$$